Current manufacturing demands faced by the aerospace industry require thinner, stronger parts in order to meet constantly more demanding standards for lowering costs, improving safety and increasing fuel mileage. As a result, manufacturers are faced with machining thin walled parts using high speed processes. Machining complex shapes with walls having thickness in the range of, for example, 0.010″ to 0.060″(0.025 to 0.15 cm). Such parts are prone to wander on a machining fixture when being drilled or milled, for example.
Some have unsuccessfully tried to address this problem using vacuum methods including the use of materials like micro-balloons. Unfortunately, these materials are relatively costly and hard to shape into intricate parts. Because epoxy resin is typically used to bind round micro-balloons comprising such older materials it cannot easily be shaped or repaired if damaged. A significant drawback is that, since such materials have inherently smooth surfaces, they do not prevent slippage of many thin-walled parts while the parts are undergoing machining.
The present invention provides a method for making vacuum tooling fixtures that solve the aforesaid problems. For the first time, the inventors herein have discovered and developed a new and useful gritty and/or abrasive vacuum media that secures thin-walled parts in place for machining, that is easily repairable when damaged, and is low cost compared to prior methods and materials.
For example, in an advantage over previously available systems the vacuum media of the present invention is made of epoxy and gritty and/or abrasive granular material which may easily be formed and patched as desired. Thus cuts or holes drilled into the granular media may be repaired as necessary for continued use.